export default function (base64Data, filename){
    // 将base64的数据部分提取出来
    const arr = base64Data.split(',');
    const mime = arr[0].match(/:(.*?);/)[1];
    const bstr = atob(arr[1]);
    let n = bstr.length;
    const u8arr = new Uint8Array(n);
 
    while (n--) {
      u8arr[n] = bstr.charCodeAt(n);
    }
 
    // 使用Blob对象创建File对象
    const blob = new Blob([u8arr], { type: mime });
    const file = new File([blob], filename, { type: mime });
    return file;
  }